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SubjectRe: [PATCH v3 1/2] tpm: fix reference counting for struct tpm_chip
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On 05.02.21 16:15, Jason Gunthorpe wrote:
>
> No, the cdev layer holds the refcount on the device while open is
> being called.
>
> Jason
>

Yes, but the reference that is responsible for the chip deallocation is chip->dev
which is linked to chip->cdev and represents /dev/tpm, not /dev/tpmrm.
You are right, we dont have the issue with /dev/tpm for the reason you mentioned.
But /dev/tpmrm is represented by chip->cdevs and keeping this ref held by the cdev
layer wont protect us from the chip being freed (which is the reason why we need
the chip->dev reference in the first place).

And yes, the naming dev/devs/cdev/cdevs is quite confusing :(

Regards,
Lino

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